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As has been talked about, I'm sure there are several solder challenged folk that would prefer a Teensy 4.0 follow on that is in a Teensy 3.5/3.6 form factor and includes the micro SD drive. I'm sure however, Paul is...

Well the T4.0 I got from Adafruit did not have pins. The PJRC version listed in their store no longer mentions providing pins, and I believe the purpose 3.2 I got from OSH park a year or two ago did not come with pins...

I haven't ordered from OSH park in over a year. In the past, when I ordered PCBs, the shipping was free. Perhaps when a Teensy is added, or you don't order a PCB, they add the charge. Or perhaps they no longer do...

Yes, if you don't need audio output via the DAC, you can leave the pins in the back of the prop shield unconnected (the prop shield only uses the DAC pin on the back row if memory serves). Note, the prop shield has...

I was over at OSH park, and I noticed that the purple Teensy 3.2 (previously 3.1) was no longer for sale. But they now have the Teensy 4.0 for sale:
https://store.oshpark.com/products/teensy-4
For USA...

You can use Wire.h.
An i2c bus is a shared bus. Each device has an address, sort of like a phone number. When the i2c master is talking to an i2c slave, it uses the address of the slave to send commands to. All...

It sounds like you might have some accidental solder bridges. Those can be hard to track down, particularly if they are bridges that are temporary depending on the pressure of the board.
Just to be sure, did you...

I recall there was a Teensy based guitar shield on tindie.com and looked it up:
https://www.tindie.com/products/Blackaddr/arduino-teensy-guitar-audio-shield/?pt=ac_prod_search
Even if you prefer to build your...

Well the display threads tends to have a lot of talk about SPI in general and using both SPI0 and SPI1 to control two separate displays (most notably two of the cheap displays that don't have a CS pin):
...

If you need optimized SPI with DMA, such as running two displays, the posts I see from KurtE, mjs513, and defragster indicate that you should put each display on a separate SPI bus:
SPI0: SCLK = pin 13, MOSI = pin...

On the Audio Shield it expects:
Ground pin on left side
Pin 6 on the audio shield (SPI Flash memory chip select), Pin 6 on the Teensy 4.0
Pin 7 on the audio shield (SPI MOSI), Pin 11 on the Teensy 4.0 (SPI...

I believe so, though I have not done it personally. I believe the inner pins for USB host are in the same order as a USB adapter within computers.
https://forum.pjrc.com/threads/37615-Teensy-3-6-USB-Host-support
...

Yeah, my soldering iron doesn't have a thin tip. But yeah, the main problem I have is my computer/reading bi-focals the difference between the two lenses is about where I would want to use for soldering and the head...

As Blackaddr says, there are various ways to do analog input.
However, if your inputs are digital you can use the I2S pins. Unfortunately, the Teensy 3.x pinouts did not list the I2S pins. Note, they overlap with...

In order to optimize the displays on Teensy 3.x systems, you will need to make sure both the CS pin and the D/C use the SPI0 fast pins. From the picture it looks like you are using pin 10 and pin 9 which are fast pins....

I was going to ask for suggestions of how to better solder those pads. For the 3.2 I like the FrankB castellated board which is fairly easy to solder (and the Bob Larkin board for 3.5/3.6 in the spirit of Frank's...

FWIW, as I posted in another thread, I rendered one of my T4's inoperable when I was trying to attach wires to the underneath pads. I'm pretty sure the problem was I extended pad #31 a little too far, and connected...

FrankB developed a MP3 library a few years ago, and added a AAC player as well. However, it was developed in the Teensy 3.2 time frame, and only plays one MP3 file at a time.
I see he made a few mods 6 months or so...

I don't use it, but if you want to program multiple Teensys all on the same USB bus, you should be able to use this software:
https://forum.pjrc.com/threads/27825-Teensy-Qt
If you need to provide a way to load...

Looks nice. It is probably more advanced than I would use, but I can see other people using it who want to do more than just play some pre-recorded sounds. For me, the primary motivation is things like costume props,...

Yeah, it likely is trying to use too much power. If you have an ammeter, you could hook it up to see the power draw.
I really like this voltage/ammeter because it has a bluetooth component, and I can connect to it...

FWIW, by cutting off all of wires soldered on to the bottom, and using solder wick to remove the solder, I was able to get it to boot again. In testing each of the solder pads in turn, it looks like all pads are...

The issue is that since pin 13 has a LED attached to it, the LED includes a resistor, and that changes the electrical characteristics of the line when trying to read from it. Hence Paul's suggestions of ways to work...

I was trying to solder wires to the underneath of one of my Teensy 4.0's. I had gotten some 7 pads soldered, and I was going back for pads 27 and 31, when evidently I put on a little too much solder in the wrong are,...

Some simple things come to mind in terms of debugging it. Note, I am a software guy, not one who does a lot of processing with the audio shield (I tend to prefer the prop shield to play simple sounds):
You only...

I don't see any electrical components on the shield other than the 2 LEDs, so it should be safe. If it add additional components, you would need to verify that the components can all work at 3.3v.
There is a seller...

At least in the past, the trouble with using the Rasberry Pi was the Raspberry Pi you would typically want to use (Raspberry Pi Zero or Raspberry Pi Zero W) from a size, cost, and power usage was hard to get in...

From your picture of the wiring, you do not have pull-up resistors installed. Some devices provide pull-up resistors, so do not. So, try adding two pull-up resistors, one between pin 18/A4 (SDA) and 3.3v and the other...

I'm not sure what I'm looking at. It doesn't seem to be a board for the Teensy, as the holes are all wrong. And I can't tell where the I2S or SPI breakouts are (and S/PDIF is not yet supported). With all of those...

If you don't want to have I2S output, and don't use the main SPI bus, but want some basic output fed into an amplifier (such as the prop shield), here is the ToneSweep program rewritten to use MQSR/MQSL. Note, the...

Have you programmed at least one sketch to your T4? As shipped, Teensy's don't enable the USB serial port in their blink sketch. I was reminded of this when I took a new T4 out of the package, and the serial port...

Obviously the big issue is supporting a filesystem from the Teensy, and others can answer that.
But in terms of storage, there are various SPI and I2C flash memory systems floating around. The question is whether...

To answer the question about using I2S amplifiers directly without the audio shield, it turns out to be pretty simple, as long as you use the default I2S TX (pin 7).
Here is ToneSweep modified for using I2S directly...

It depends on how fast you need the conversion to. There are a bunch of level shifters that are made for i2c/spi/uart type conversions that will do the transfers in either direction. But they have limitations in terms...

I've been thinking of soldering up a prototype board for Teensy 4.0 that brings out 2 of the three SPI buses (for uncanny eyes) and also brings out sound. Now, generally I do these one-off boards where I have several...

For single integer values, you should not be using 'PROGMEM' at all. Just use 'const'.
Going back in history, 'PROGMEM' comes from microprocessors like the Arduino 8-bit AVR processors (like the Uno), had what is...

Well if you are using the pin in the back that on the Teensy 3.1/3.2 is a DAC (digital -> analog converter) that can play sounds when ampified, that is your problem. The Teensy 3.0 did not have a DAC. Instead the pin...

Since, Adafruit has its own machines with DMA and they now have an Adafruit_ZeroDMA library that abstracts this in some sense. If we can have the same public names (using a different include file), it may be easier in...

Cool. I need to wire up my second Teensy 4 to export at least pins 26 and 27. If I get motivated, hopefully I can run it against the Monster M4SK that I bought. I expect the Teeny 4.0 (M7) is faster than Adafruit...

Well Paul hasn't announced a bootloader chip yet for Teensy 4.0. Presumably in time he will, but for now, your only option is building a custom 3.6.
Note, on 3.6, only single precision floating point is supported in...

In other processors that have split registers like this, you read the seconds value twice, and if the versions are different, you loop back, and re-read all three. I.e. something like:
unsigned long seconds,...

It depends on how optimized the drivers are and whether the devices do things like tri-state MISO properly.
Assuming you have done all things in the quoted document (pull-up resistors on the CS pins, verified the...

The only way to do it is to have two different names for the sections, one name for sections that contain functions, and another name for sections that contain data, and then modify the linker script so it links both...

Depending on your speed/power/etc. requirements, you could consider using something like a Teensy LC to control the display, and have the main teensy communicate to the LC what to write, and let the LC deal with menus,...

I tend to use prototype boards and solder in connections for various things. For example my current board has:
2 sets of female headers with 24 columns for mounting Teensy 3.x, LC, or Teensy 4.0;
An extra row of...

If you haven't already done so, please look at the following document:
https://www.pjrc.com/better-spi-bus-design-in-3-steps/
Note, it appears the standard SD library does not use SPI.beginTransaction, but if...

The Teensy 4 does not have alternate I2C pins like the previous Teensy LC/3.x microprocessors did. So for the first i2c port, you have to use pins 19 and 18.
However, the Teensy 4.0 does have a second i2c that are...

Some of the Adafruit processors have a flash memory system that you can read like a SD card (similar to the 8 megabyte flash memory in the Teensy prop shield, or the flash memory system you can solder onto the audio...

In the past, pin D33 was special. Here is a quote from Paul from the 3.1 time frame:
Pin 33 on the Teensy 3.0/3.1 is special. It defaults to a non-maskable interrupt (active low) with a pullup resistor. When it's...

Well then I'm out of ideas, other than the general check your connections for connectivity. I've had breadboards where certain slots no longer would pass current and solder connections that came apart.
Note, the...

Generally on Teensy's you need 2 pull-up resistors, one between SCL (pin 19/A5) and 3.3v, and the other between SDA (pin 18/A4) and 3.3v, unless one or more devices on the i2c bus already has pull-up resistors. The i2c...

Yes, you should be able to use a MCP23017, as long as you avoid i2c addresses 0xA and 0x1A. I2C is a shared bus system, where each device has its own address, and it typically ignores data to/from other devices on the...

Well, it wasn't Limor Fried (i.e. Lady Ada), but Phillip Burgess, author of the various versions of uncanny eyes (Teensy, Pi, Hallowing, and now Monster M4SK), has a version up for the Monster M4SK or Hallowing:
...

In the T3.x case, you needed two pins, one for CS and one for D/C for the devices that do DMA buffering. I believe in the 4.0 case, you don't need a special pin for D/C. But I really haven't delved into the internals.

Well you can download any program into the Teensy 4.0. You don't have to use the Arduino IDE, as long as you build a program that the downloader recognized. However, you can't change the actual bootloader that is on a...

I don't believe there is a reset pad.
The on/off thing is new. If you connect the on/off pin to ground for around 5 seconds, the Teensy will turn itself off. It won't turn on until either the power is cycled, or...

I believe the special CS pins are only if you use device drivers that use DMA, such as several of the displays (ST7735, ST7789, etc.).
There appears to be only one CS pin for DMA per SPI bus. If you have normal SPI...

Paul has to be the one to answer this. But I suspect it may have to do with the availability of the chipset used in the Teensy 3.2. If NXP stops selling that chip, Paul will have to stop selling Teensy 3.2s once his...

I don't think the Teensy 4.0 has the alternate SPI pins like the Teensy 3.x/LC had. That's why the beta users were given a break out board that mapped the Teensy 4.0's pins to the pins the audio shield used.
Note,...

Well the 3.2 typically runs at 96Mhz, and the LC tops out a 48Mhz. Perhaps the Teensy 3.2 is running to fast for the device.
Perhaps you need pull-up resistors on the CS pins.
Perhaps you have a connection issue...

It has worked for me in the past, when I hooked up the RTC and soldered in the crystal. I would look into the solder joints on the crystal and Vbat/Ground. I dunno, maybe the crystal suffered from too much heat while...

Paul wrote this article some time ago, about better SPI design:
https://www.pjrc.com/better-spi-bus-design-in-3-steps/
The simplest step is to try and use pull-up resistors on each of the chip select pins. I...

Somebody else asked the same question over in the 1.47 announcement thread. You might want to watch that thread as well in terms of getting an answer:
https://forum.pjrc.com/threads/57216-Teensyduino-1-47-Released

Are you using the Adafruit_RA8875 or RA8875 libraries. Typically the Adafruit libraries should work but they don't have Teensy specific optimizations. Unfortunately, the author (sumotoy) of the Teensy specific library...

There is an urban legend that states Apple bought a Cray whatever to help design their next computers doing layout, etc. while Seymour Cray is said to have replied that he used his Apple Mac (or whatever was the current...

You can disconnect the USB power from the Teensy by cutting the solder pad underneath the Teensy. It is the solder pad next to the VIN (5v) pin (see the back of your Teensy card). Then the Teensy will only be powered...

I suspect it is too early for any of the boards being designed to be available yet. There are some boards that you can send the gerber files to a PCB printer (like OSH park in the USA) and it will print up the board,...

For long term usage however, you would be advised to start transitioning to the Teensy LC (or 3.2 or even 4.0). Paul has posted that the Teensy 2.0 is nearing the end of its lifetime, so for new development, it would...

Unfortunately, the only pins that are brought out on the Teensy 4.0 are Teensy pin 10 (B0_00) for MQS_RIGHT and Teensy pin 12 (B0_01) for MQS_LEFT.
Page 309 of the manual states the alternate pads for MQS_RIGHT to...

I suspect this is just impossible, unless you resort to bit-banging (i.e. manually turning the pins on/off and not using the hardware supports, which would be sloooooooooooow). You have to understand that these modern...

There is the ever popular question: have you added pull-up resistors or does your device have pull-up resistors? You would want one resistor between SCL and 3.3v, and another between SDA and 3.3v. Typically for a 3.3v...

These are power rails, similar to the power rails on a traditional breadboard. Typically one rail would be ground and one rail would be 3.3v. Typically you would solder either a row of female/male headers on the data...

I was thinking that perhaps there is enough other stuff declared static, and the buffer array is crossing the line between the two memory halves. Print out the begin and end addresses in hex to see if you are crossing...

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About MichaelMeissner

Biography:

I am a computer programmer that has worked on compilers for over 33 years. I have been working on the GNU GCC compiler for over 20. Outside of work, I tend to be known for my steampunk camera (see http://www.steampunkmike.org for more details).